T-Iso, short for Isochrysis galbana (Tahitian strain), is a golden-brown flagellated microalga packed with DHA. That makes it one of the most important species in marine aquaculture. It's especially valued for feeding bivalves, copepods, rotifers, and larval fish thanks to its small cell size (around 4 to 6 microns), high digestibility, and excellent enrichment potential.
What you'll need
- T-Iso starter culture
- F/2 or Walne's nutrient mix
- Saltwater at 1.018 to 1.022 SG
- Full-spectrum light (6,500 to 10,000K, 12 to 16 hours per day)
- Air pump with rigid airline tubing
- Sterile container (HDPE or glass)
- Optional: a gentle stir plate to prevent cell settling
Culturing steps
Prepare the culture medium. Mix RO/DI water with marine salt to roughly 1.020 SG. Add your nutrient mix (F/2 is the standard choice) and let it sit until fully dissolved.
Inoculate. Add the T-Iso starter to your prepared medium once it's at room temperature. Swirl gently to distribute.
Aerate gently. T-Iso is fragile and prefers fine, low-turbulence aeration. Avoid strong bubbling, which can shear the cells.
Light it up. Provide 12 to 16 hours of full-spectrum light each day. Keep the temperature stable, ideally between 20 and 26°C. Avoid overheating the culture.
Monitor growth. A healthy culture shifts from light tan to golden-brown over 4 to 7 days. It should smell clean, not foul. A sour or off smell is your warning that something's gone wrong.
Harvest. Decant or run through a fine mesh sieve. Use within a few days or refrigerate. Always keep a backup culture going so a single crash doesn't wipe out your supply.
Tips for success
- Sanitise all gear before use. T-Iso is one of the easier strains to contaminate, and it crashes faster than most.
- Avoid stagnant zones. T-Iso clumps and settles without movement, which can suffocate the cells underneath.
- Scale up gradually. Start small (around 500 mL) and step up to larger volumes as the culture establishes.
Why culture T-Iso?
- High in DHA. Ideal for enriching pods and rotifers.
- Critical for bivalves and larval stages. Many oysters, clams, and fish larvae rely on it specifically.
- Small cell size. Compatible with the broadest range of filter feeders and small-mouthed grazers.
- Great support strain for long-term copepod cultures.
If you're serious about breeding marine livestock or want to support a thriving reef food web, culturing T-Iso is one of the best moves you can make.
